This invention pertains to air precleaners. More particularly, this invention relates to an air precleaner employing a vane assembly and a rotating impeller assembly.
Air precleaners are used for removing particulates from the air prior to introducing the air through an air cleaner or filter, which is connected to a carburetor or air intake structure, of an internal combustion engine. Precleaners are generally located on the open inlet side of the air intake pipes or stacks of an internal combustion engine. The function of the precleaner is to remove as many contaminants from the air as possible before it flows into an air filter medium upstream from the internal combustion engine.
All precleaners operate on the principle of centrifugal separation. Outside air, with its entrained contaminants, enters the precleaner from the vacuum created by the engine. The air and contaminants traverse a set of fixed, static, vanes which cause the air to circulate at a great speed. Centrifugal force throws the contaminants and moisture towards the outer wall of the precleaner. The contaminants follow the wall until they reach an opening where they are discharged back into the atmosphere or collected. Clean, dry air is then allowed to enter the air filter and subsequently the internal combustion engine.
As precleaners work on centrifugal separation, greater air flow velocity will result in better separation between air and contaminants. The best contaminant separation happens when the engine is running at a high speed (in rpm) thus causing a high velocity of the air flow coming into the precleaner. As the velocity of air flow decreases, the centrifugal force on the contaminants also decreases reducing the separation efficiency of the precleaner.
Undesirable contaminants in the atmosphere include particulate matter such as dirt, dust, sand, snow and the like. While most engines include air filters which are meant to remove such contaminants from the air that feeds the engine, engine precleaners are also used in order to extend the life of the air filter and extend the engine's life while at the same time improving fuel economy.
Several different designs of air precleaners are commercially available in the marketplace. In one design, an air precleaner uses a rotatable impeller or spinner to separate particles from air, discharge the dirty air and particle mixture circumferentially from a housing and direct the clean air to the air intake structure of an engine. The clean air moves centrally through a stack to the engine in response to a vacuum pressure on the air moving to the engine. This air precleaner has an air inlet vane assembly located in the bottom of the housing. The air flows upwardly in a circular path into a centrifugal separation chamber and then turns downwardly into the centrally located clean air exit opening. The impeller is used to pump air and particulate matter out through side discharge openings. This type of air precleaner, however, does not take full advantage of the power of the vortex-like air flow in the mouth region of the clean air outlet passage.
Known air precleaners have also included a design in which air flows into the top of the air precleaner and flows axially downwardly through the precleaner and into the intake stack of the engine. Although such precleaners may perform adequately with respect to particulate material, this is sometimes accomplished at the expense of reduced air flow. In other words, the precleaner itself may become an air restriction. The known precleaners of this type do not use static vanes which cause the air to circulate at as great a velocity as the vanes could. Also, some precleaners are only useable when positioned in one orientation, i.e. positioned on a vertical axis or positioned on a horizontal axis.
Accordingly, it has been considered desirable to develop a new and improved air precleaner which would overcome the foregoing difficulties and others while providing better and more advantageous overall results.